Abstract: In this paper,Psammosilene tunicoides,an endemic species to China,was cytologically studied for the first time.The morphology of the nuclei at resting stage was categorized to be simple chromocentre type.The morphology of mitoticprophase chromosomes was categorized to be the interstitial type.28 chromosomes were observed at the mitotic metaphase,and 14 bivalent chromosomes were observed at diakinesis.So,the basic chromosome number was confirmed to be x=14.Psammosilene tunicoides is different from Silene rubicunda in the basic chromosome number and the morphology of the nuclei at resting stage and mitoticprophase chromosomes,because Silene rubicund has the basic chromosome number of x=10 and 12,and its nuclei at resting stage and mitoticprophase chromosomes is sparsely diffuse type and continuous type respectivrly.

Key words: Psammosilene tunicoides